Which buoys may be lettered and not numbered?

Preferred channel buoys can be lettered rather than numbered. This is significant because these buoys are used to indicate the preferred route of navigation, helping mariners make better decisions about where to steer their vessels. The lettering system provides an additional layer of information, allowing for easier communication and reference among mariners familiar with the local waterways.

In contrast, safe water buoys generally use a number system to indicate their location effectively, while special purpose buoys often have specific markings or colors to convey their unique messages related to safety, hazards, or other purposes. Lighted buoys also follow a different system that typically involves numerals rather than letters, making it easier to identify their positioning during low visibility conditions. By utilizing letters, preferred channel buoys can maintain clarity in navigating specific routes, which is crucial for safe vessel operation.